Update picture-in-picture settings to match mocks.

- Removing switches in top-level picture-in-picture settings, adding
  details screen for each app which contains the switch and some
  additional information.

Bug: 35957404
Test: make -j40 RunSettingsRoboTests
Change-Id: Ib22df8a52ab857e071ec43dd3e5d1f5282db35cb

src/com/android/settings/core/gateway/SettingsGateway.java

@@ -52,6 +52,7 @@ import com.android.settings.applications.InstalledAppDetails;
 import com.android.settings.applications.ManageApplications;
 import com.android.settings.applications.ManageDomainUrls;
 import com.android.settings.applications.NotificationApps;
+import com.android.settings.applications.PictureInPictureDetails;
 import com.android.settings.applications.PictureInPictureSettings;
 import com.android.settings.applications.ProcessStatsSummary;
 import com.android.settings.applications.ProcessStatsUi;
@@ -218,6 +219,7 @@ public class SettingsGateway {
             WallpaperTypeSettings.class.getName(),
             VrListenerSettings.class.getName(),
             PictureInPictureSettings.class.getName(),
+            PictureInPictureDetails.class.getName(),
             ManagedProfileSettings.class.getName(),
             ChooseAccountActivity.class.getName(),
             IccLockSettings.class.getName(),